The Secrets We Keep

Those close to Paige Birgfeld knew her as a loving mother of three young children and an energetic small business woman. But police revealed last weekend that Birgfeld, a Colorado mother of three, allegedly led another life, one kept secret from her friends and family: She ran a local escort service.

Birgfeld disappeared June 28. Her burned-out Ford Focus was found three nights later, on the side of a road two miles from her upscale home. Police appear to have few clues about the case.

But if the conclusions drawn by local police are correct, the 34-year-old Colorado resident appears to have joined the ranks of many seemingly ordinary Americans who lead hidden lives. News reports abound with stories of men with multiple families, married teachers who have illicit affairs with their students, or otherwise upstanding men and women who struggle with hidden drug problems or visit, or work for, escort services.

The details of the Birgfeld case are still emerging and it's too soon to know what drove her to allegedly work in the escort business.

But forensic psychologists say that people who lead dual lives are often driven by many of the same factors, including easy money, possible personality disorders and the thrill of illicit and sometimes dangerous activities.

"There's no one profile," said Gregg McCrary, a retired criminal profiler with the FBI. "It's usually a combination of things -- money, emotional needs, the need to have a secret life, the need to be risk taking."

That duality can lead to dangerous consequences. "If the secret life is more rewarding than the normal life, then you may get addicted to the secret life," said forensic psychologist Katherine Ramsland. "The two lives are going to clash one way or the other."

Experts who spoke with ABC News discussed some of the common factors that can lead otherwise average people to participate in illicit activity such as escort services. Those factors may or may not be in play in the Birgfeld case, and none of the experts was intimately familiar with the details of her case. Some forensic psychologists pointed to significant differences between running an escort service and some other types of secret activity, like an affair with a student.

Police Suspect Foul Play

Authorities now say they believe Birgfeld went by the name "Carrie" when dealing with customers of "Models Inc.," an escort service that police say she ran.

Until Saturday, authorities in Colorado were treating Birgfeld as a missing person, even suggesting that she may have staged her own disappearance. But new information about her escort agency, combined with a lack of any evidence indicating she voluntarily went missing, altered the investigative track over the weekend. Police are investigating potential clients who may have dealt with Birgfeld around the time she disappeared.

"We so far haven't found a single piece of evidence that indicated she left on her own free will," said Heather Gierhart, a spokeswoman for the Mesa County Sheriff's Office.

Authorities are also moving closer to ruling out the involvement of Birgfeld's two ex-husbands, one of whom is the father of her three children. Birgfeld had recently written about one of her ex-husbands on an online forum for consultants who sell Pampered Chef products, suggesting that she felt uncomfortable having him close to her children. But police now suggest it is unlikely that he was involved in her disappearance.

'The Money Is Fantastic'

Though it is still unclear what led Birgfeld to allegedly run Models Inc., one possible -- maybe obvious -- explanation for behavior like Birgfeld's is money.

"Generally the primary motive is money," said ABC News consultant Dr. Michael Welner, a forensic psychiatrist and the head of the Forensic Panel, adding that the escort business would allow someone in Birgfeld's position to quickly make a lot of money without any advanced education or training.

"Without interviewing her, my only frame of reference is what comes up time and again," he said. "And time and again the money is fantastic and you can't beat it."

Police say Birgfeld worked several jobs. In addition to the escort agency, she ran a chef's consulting business, taught dance to preschoolers and sold baby products.

The Grand Junction Sentinel reported that investigators have also visited a downtown office kept by Birgfeld, where they found a massage table and what appeared to be acupuncture equipment. Police would not confirm or deny the report

Joel Dvoskin, a forensic psychologist and the president of the American Psychology-Law Society, agreed with Welner's assesment.

"Logically, it's more likely that there's a financial cause," he said, adding that it would be too difficult to speculate on the myriad possible psychological reasons that Birgfeld might work at an escort service, given how little is known about her. "Money is often why people do things."

A Reprieve From a 'Boring' Life?

Some people who have engaged in similar illicit behavior have been driven by psychological disorders and a desire to add excitement to their lives, experts said.

"More often than not, part of it is the thrill, adding excitement to an otherwise 'boring' life," said McCrary. "They want to have a dark secret, to walk on the wild side a little bit."

Working in the sex trade in particular can offer an allure of danger. "They acquire an aura of being sexy, which you don't necessarily retain after marriage and motherhood," said Ramsland.

Welner, though, disputed that characterization, saying that the sex workers he has treated are not attracted to the danger of the work.

What little is known about Birgfeld also appears consistent with some personality disorders, said Dr. Elliot Atkins, a forensic psychologist. Atkins suggested that working several different jobs while raising three children could be consistent with a need for approval and affirmation or with the manic activity associated with bipolar disorder.

People with bipolar disorder are often easily bored and are stimulated by stress of balancing different parts of their lives. They often engage in several projects at once and often engage in sexual indiscretions, he said.

"In this case, one of the things we see is that she appears to be somebody who's very busy, engaged in multiple activities and multiple relationships," he said. "What we see is an individual who has an extremely high level of energy, or need for excitement."

All of Birgfeld's different activities are consistent with the "grandiose thinking of someone in a manic state," Atkins said.

Stress and Anxiety

The stresses of leading a hidden life often leads people to unravel and may lead to anxiety, depression and other mental illness.

"Sometimes they react with violence, sometime they will just slip away and start over somewhere," said Ramsland.

"If you have any conscience at all, you do begin to feel the guilt," she said.

Welner said that people who work in the sex industry often struggle to fit in to their communities. "Often they long for a day when they will have a legitimate life," he said.

It is still too early to tell which of the possible explanations best describes what happened to Birgfeld. And Dvoskin warned that there are significant differences between behavior like having an affair with a student, which can be motivated by a lack of impulse control, and running an escort service, which requires much more planning.

Until more is known, Birgfeld's friends and family will probably continue to be surprised by how little they know about the young woman they thought they knew.

Forensic psychologist Martin Williams wondered, "You have to ask, is the escort service the exception or is the family life the exception?"

ABC News Consultant Dr. Michael Welner is chairman of The Forensic Panel, a national forensic science practice. He is developing an evidence-based test called the Depravity Scale,, which invites Americans to participate in surveys that are used to form a legal standard of what represents worst crimes.